Multi-Component Induction (MCI) logging can provide formation anisotropic-resistivity information, which can be used to analyze sand-shale laminations, for example. However, the MCI measurements are highly sensitive to borehole effects, especially for non-ZZ measurements of short-spacing arrays operated at high frequencies.
For conventional (ZZ) induction tools, an operation known to those of ordinary skill in the art as “borehole correction” is useful to correct the MCI measurements, based on a look-up table of MCI responses. In standard (ZZ) induction tools, the model parameters that are used in building a borehole-correction look-up table include: Rm, Rf, D, d, which represent mud resistivity, formation resistivity, borehole diameter, and tool eccentricity, respectively. For MCI however, there are more parameters: Rm, Rv, Rh, A, D, d, ϕ, θ, and φ, representing mud resistivity, formation vertical resistivity, formation horizontal resistivity, the formation anisotropy ratio (A=Rv/Rh), borehole diameter, tool eccentricity, strike angle, dip angle, and tool eccentricity angle (or azimuth), respectively. Due to the larger number of parameters, the look-up table for an MCI tool requires four additional dimensions, producing a very large database. Moreover, the physics of anisotropic wave propagation is more complicated than the isotropic case, and modeling each case takes a significant amount of computational time.